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Clinker Cooling Equipment

Grate Cooler

The workhorse of modern cement clinker cooling — a reciprocating-grate cooler that rapidly quenches hot clinker from 1,400°C while recovering ≥72% of its heat as secondary combustion air. With capacities from 600 to 10,000 t/d, the grate cooler is essential for fuel-efficient, high-quality clinker production.

≥72%Heat Recovery
600-10,000 t/dCapacity
ReciprocatingTravelling / Rotary
1,400→100°CClinker Cooling

Product Overview

About the Grate Cooler

The grate cooler is the clinker cooling equipment installed at the discharge end of the rotary kiln. Hot clinker nodules (1,300–1,400°C) fall from the kiln onto a moving grate, where a powerful stream of cold air is blown upward through the clinker bed. The air cools the clinker to below 100°C — safe for conveyor transport and cement grinding — while itself being heated to 1,000–1,200°C and routed back as secondary air to the kiln burner and tertiary air duct.

This heat recovery is what makes the grate cooler indispensable: by returning hot combustion air to the kiln, it directly reduces the fuel the kiln burner must supply. A well-designed reciprocating grate cooler recovers 72% or more of the clinker's heat, contributing to the lowest possible heat consumption per kilogram of clinker in modern NSP lines.

Rapid cooling also preserves clinker quality. Fast quenching "freezes" the high-temperature mineral phases (C₃S, C₂S) and prevents unwanted belite conversion, producing harder, more grindable clinker with better cement strength. LIMING Machinery manufactures reciprocating, travelling, and rotary grate coolers covering 600 to 10,000 TPD.

Types of Grate Coolers

Grate coolers are classified by the mechanism that moves clinker across the grate.

Reciprocating Grate Cooler

The modern standard for NSP cement lines. Stationary grate rows alternate with reciprocating rows that push clinker forward. Excellent heat recovery (≥72%), stable operation, and high capacity — suitable for 600 to 10,000 TPD lines.

Travelling Grate Cooler

Uses a continuously moving grate chain to transport clinker. Older design suited to smaller or retrofit lines. Simpler mechanics but slightly lower heat recovery than reciprocating types.

Rotary Cooler

A rotating drum cooler (similar to a small rotary kiln) used for special applications and smaller capacities. Less common in modern large cement plants but useful for certain lime and specialty clinker processes.

Key Benefits

Advantages of the LIMING Grate Cooler

Engineered for high heat recovery, rapid clinker quenching, and reliable continuous duty.

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High Heat Recovery (≥72%)

Optimized clinker-bed thickness and air distribution recover 72% or more of clinker heat as hot secondary air (up to 1,200°C), directly reducing kiln fuel consumption and lowering overall heat consumption per tonne of clinker.

Rapid Cooling

Intense cold-air flow quenches clinker from 1,400°C to below 100°C within minutes, preserving the desired C₃S/C₂S mineralogy, preventing belite conversion, and producing harder, more grindable clinker with better cement strength.

Stable & Efficient Drive

Hydraulic or mechanical reciprocating drive with frequency-controlled grate speed adjusts clinker residence time to match kiln output. Sealed air chambers prevent short-circuiting and ensure uniform air distribution.

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Wear-Resistant Grate Plates

Heat-resistant cast-steel grate plates (LIMING supplies genuine grate cooler plates) withstand 1,400°C clinker and abrasion, ensuring long service life and minimal unplanned downtime.

Grate Cooler Specifications

Select a model based on your daily clinker output. LIMING customizes grate area, drive type, and air distribution for each project.

Model Capacity (t/d) Grate Area (m²) Heat Recovery Clinker Out Temp (°C) Type
GC-60060012≥70%≤100Reciprocating
GC-10001,00018≥72%≤100Reciprocating
GC-15001,50026≥72%≤100Reciprocating
GC-20002,00034≥72%≤100Reciprocating
GC-25002,50042≥72%≤100Reciprocating
GC-30003,00052≥72%≤100Reciprocating
GC-40004,00068≥72%≤100Reciprocating
GC-50005,00086≥72%≤100Reciprocating
GC-60006,000104≥72%≤100Reciprocating
GC-80008,000140≥72%≤100Reciprocating
GC-1000010,000178≥72%≤100Reciprocating

* Specifications are for reference only. Actual performance depends on clinker properties and kiln output. Contact LIMING for model selection.

How It Works

Working Principle of the Grate Cooler

The grate cooler operates on the principle of cross-flow convective heat exchange. Hot clinker moves horizontally across a grate while cold air is blown vertically upward through the clinker bed — the two flows transfer heat rapidly and efficiently:

  1. Clinker feed: Hot clinker nodules (1,300–1,400°C) fall from the rotary kiln discharge onto the front of the moving grate. A spreader distributes the clinker evenly across the grate width to ensure uniform bed thickness and air flow.
  2. Cold air injection: Powerful under-grate fans blow ambient air upward through the clinker bed. The air is divided into multiple compartments so that each zone receives the optimal flow for the local clinker temperature.
  3. Heat exchange & secondary air recovery: As cold air passes through the hot clinker bed, it absorbs heat and is heated to 1,000–1,200°C. This hot secondary air is collected in the upper hood and routed back to the kiln burner (and tertiary air duct to the precalciner) for combustion — directly reducing fuel consumption.
  4. Clinker discharge: The reciprocating grate slowly pushes the now-cooled clinker (≤100°C) toward the discharge end, where it falls onto a conveyor for transport to the clinker store or cement mill. Exhaust air from the cooler is cleaned in a bag filter or ESP before release.

Grate Cooler FAQ

Why is rapid clinker cooling important?
Rapid cooling preserves the desired mineralogy of clinker — freezing the high-temperature C₃S and C₂S crystal structure and preventing unwanted belite conversion. It also reduces clinker temperature to a level safe for cement grinding and improves grindability, lowering downstream grinding energy. Slow cooling would degrade clinker quality and cement strength.
How does the grate cooler recover heat?
Cold air blown through the clinker bed absorbs heat, becoming hot secondary air (up to 1,000–1,200°C) that is routed back to the kiln burner and tertiary air duct for combustion. This recovers 72% or more of the clinker heat, directly reducing fuel consumption — one of the most important efficiency levers in a modern cement plant.
Which type of grate cooler should I choose?
Reciprocating grate coolers are the modern standard for large NSP lines, offering high heat recovery and stable operation. Travelling grate coolers suit smaller or older lines. Rotary coolers are used for special applications. LIMING engineers will recommend the optimal type based on your capacity, process, and retrofit needs.

Need a Grate Cooler for Your Cement Line?

Tell us your daily clinker output and process type. Our engineers will recommend the optimal grate cooler model and configuration.

WhatsApp: +86 153 3380 7511 [email protected]
WhatsApp: +86 153 3380 7511 [email protected]